The immobilization of enzymes in inorganic support is expected to provide breakthroughs in the area of heterogeneous catalysis. Biological molecules such as enzymes are outstanding catalysts with very high catalytic power and very high specificity. However, they are barely used, because of their fragility. Appropriate immobilization helps to maintain their quaternary structure, to protect them against external environment, to recover the products and to develop process in continuous flow. There are five kinds of enzymes: very stable enzymes, enzymes with co-factor self-regenerated, enzymes with co-factor no self-regenerated, very fragile enzymes, polyenzymatic systems. Only, the immobilization of the first kind of enzymes has been widely studied in inorganic supports [1]. We proposed a new way of enzyme encapsulation in silica supports, which has allowed to encapsulated different kind of active enzymes: very stable enzymes (lipase [2,3], hemoglobin), very fragile enzyme (Alcool dehydrogenase [4]), polyenzymatic systems (GOD and HRP) in oxidation reactions, which open the route to new catalytic processes.Our encapsulation method, is a new concept of sol-gel synthesis using egg lecithin (natural phospholipids) as self-assembling templates for silica, and sugar to protect the enzymes. Two different kind of nanostructures were synthesized: a three dimentional isotropic structure with cavities of 6 nm, called Sponge Mesoporous Silicas, and 7 nm particle size porous Nanocapsules of Silicas, named (NPS). Both structures have been compared to classical immobilization technics and may constitute a new generation of very selective catalysts.

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[1] M.T. Reetz, et al., Adv. Synth. Catal. 2003, 345, 717. [2] M. Mureseannu, A. Galarneau et al., Langmuir, 2005, 21, 46. [3] A. Galarneau et al. New J. Chemistry, 2005, 30, 562. [4] A. Galarneau et al. Microporous Mesoporous Mater., 2007, 104, 103.

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